Brisson (1762) was ruled unavailable (International Commission on Zoological Nomenclature, 1955a); however, Lutra was ruled as still available (ICZN, 1998). Pocock (1921c, 1941a) recognized Lutrogale Gray, 1865, and Hydrictis Pocock, 1921. Harris (1968) and van Zyll de Jong (1987, 1991a) considered lutra, maculicollis, and sumatrana to represent a single monophyletic group; furthermore, van Zyll de Jong's analysis supported separation of perspicillata from other Lutra, which is followed here. Van Zyll de Jong (1972) referred New World otters to Lontra (see comment therein). McKenna and Bell (1997) included Lontra in Lutra; otherwise allocated according to McKenna and Bell (1997).